High
LF on Ideal Icos

Your boiler is failing to ignite because it cannot detect a flame, meaning your heating and hot water will stop working until the issue is resolved.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

If the boiler does not light after 3 attempts the fault codes L F will be displayed.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

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